Monthly Archives: July 2013

Often with a change of month comes a change of weather. And weather models this morning suggest this phrase will hold true.

Looking back over the last ten years August has been the wettest summer month on five occasions. Given that June rainfall was just 38% of average and July rainfall currently (as I write this on 25th) just 28% of average, it is not surprising that August could potentially be the wettest summer month.

The Atlantic looks like it will have cranked back into action by the first week of August bringing us a period of more unsettled weather – a more mobile westerly flow which means cooler conditions than we experienced during most of July.

The first week looks the most unsettled – no huge rainfall totals though there will be rain or showers around, some of them potentially thundery. Temperatures in the low 20s – though up to 25C on any brighter days.

The second week could start quite thundery with potential for a heavy downpour. After this I would expect the Azores high to ridge northwards settling down the weather to give possibly the best weather of the month during the third week – temperatures still in the low to mid 20s with lots of sunshine around and cool nights.

As the high pressure shifts, bringing a more east or south-easterly flow, days could become briefly very warm at the start of the fourth week. However the high pressure could start to drift north as the wider pattern begins to respond to a very active US hurricane season. Though it is a long way off all that extra energy in the Atlantic will begin to feed through to us at the end of the month, turning things unsettled again in time for the August Bank Holiday. September could be very wet indeed.

So in summary the buzzword for August is average overall with decent sunny summer’s days coupled with the odd rainy or showery day. No return of the heatwave – but also not the washout of the last few summers.

Average max temp: 22.5C (normal)
Average min temp: 12.5C (slightly below normal)
Rainfall: 57mm (normal) – this estimated total could be quite conservative in the event of any potent thunderstorms

It was the storm that preceded the hottest day of the year when the temperature briefly touched 34C in Wanstead – that’s higher than the official recognised figure of 33.5C at Heathrow and Northolt.

This image by MeteoX shows the storm right over Wanstead

Earlier people all around town and across the country wilted in the heatwave waiting for news on the royal sprog, many of them ignorant that things were about to go bang. But no matter – it’s days like this they say is good to bury bad news – so the weather, it seems, decided to get in on the act too. The first spots of rain fell on an exhausted crack Sky News commentary team outside Buckingham Palace just before midnight. About the same time reports started coming in of thunder in Canning Town and Poplar – but all went quiet after three flashes. Then 11.58pm reports of rain in Luke Howard’s old haunt – Plaistow. My own ride back from town saw reasonably heavy, if somewhat shortlived, rain in Southwark. Yet by the time I reached Aldgate the ground was dry. Things began to liven up again at 1.30am – distant rumbles of thunder getting closer – further reports of multiple thunder, lightning and heavy rain with hail mixed in at 1.45am. Then, bang, the storm hit Wanstead. I failed to get any footage of the event because of the ambient light washing out every shot. Multiple crashes of loud thunder followed by, at one point, dazzling lightning flashes. You know how close a storm is by counting the seconds between lightning and peal of thunder. At 1.51am I barely counted to one between a dazzling flash and one of the loudest cracks of thunder I’ve heard. Only 6.5mm of rain was recorded, though this fell at a rate of 60mm/hr – the highest rate since I put the meteo live online last November. It doubled the previous highest rate! There followed frequent, distant rumblings of thunder to the east along with copious flashes and occasional bursts of rain. Epping recorded 19mm in two storms at 5am and 6.30am. The thunder and oppressive humidity made sleep difficult. And judging by the number of bleary eyes on the school run this morning I wasn’t alone. The were other storms around London and the UK – a notable one in Brixton precipitated this account on Brixton Buzz. And Steve Brice managed to capture the lightning in Gillingham, Kent. Pershore in Worcestershire recorded over 56mm of rain in 3 hours while lightning damaged rail networks. It was one of the most dazzling displays I can remember – certainly the best since probably 2000 if not before. People often ask me what first got me interested in the weather. Until last night I’d almost forgotten that thunderstorms were one of the main attractions. A night to remember – just like the overnight storms in the Eighties I remember as a lad. Scott Whitehead @wanstead_meteo http://www.wansteadweather.co.uk with thanks to ‏@loveloughtonfor storm updates The following charts show the cell well. The 2mb pressure drop, the 60mm/hr rainfall rate, the 2C dive in temperature, and the sudden gust of wind This pressure drop is also reflected in the temperature fall at the same time: 2C in a matter of minutes.

The boating lake is popular with families and hosts an array of wildfowl

Remember the time when most local parks had a lido – or at least a kiddies paddling pool?

Growing up in the area I remember being spoilt for choice for an outdoor swim – Valentines park, Barking park, Leys, and Larkswood to name a few. Barking, thanks to a lottery grant, has recently reopened as a ‘splash park’. All very nice – but its not a proper lido.

When Valentines park pool closed in 1994 there was outrage that yet another of London’s once grand leisure facilities was going the same way as many other lidos which closed in the seventies and eighties. A petition to retain the pool signed by over 2,000 people fell on deaf ears – the powers that be unwilling to finance repairs that were estimated at £250k. The 150ft by 50ft H. Shaw-designed facility was demolished at a cost of £26k in 1995.

I’d never thought about the background behind Valentines pool until I chanced upon some info. The idea of a swimming pool in the park was first proposed in July 1923, at an estimated cost of £7,700. The council at that time, however, decided against this proposal and recommended that such an open air swimming pool be built as part of the scheme for the new High Road baths. However, in October 1923 a revised estimate of £5,500 for a pool in the park was submitted and it was decided to that work could be provided for local unemployed during the winter of 1923/24 in conjunction with the Unemployed Grants Committee. In December 1923 sanction to apply for the loan was received from the Ministry of Health and work commenced on the old gravel pit. The swimming pool was officially opened to the public on Saturday, August 2, 1924.

Perhaps this could be the way forward for a new pool – utilise the unemployed to dig in for a cooler summer? In the event and with advances in earth moving machinery I would doubt this would be politically possible to implement. But with lottery funding, council leadership and public will – surely it is possible?

A design sympathetic with the Grade II landscape on the Register of Parks and Gardens of Special Historic Interest, that hosts the excellent Valentines Mansion, would surely be a vote winner for any local politician. Rather than a knee-jerk reaction to the heatwave which has seen temperatures widely exceed 30C the past four days this is a genuine appeal to Redbridge and other local authorities to at least consider bringing back these facilities that used to be widely enjoyed by the masses, many of them affordable or even free of charge.

They don’t have to be expensive white elephants – the few lidos that were spared the axe or have reopened, such as the London Fields lido which reopened in 2006, are well-run facilities that are used all year round. Anyone who’s tried to use a public swimming pool recently, indoors or out, would know that demand often seems to outstrip supply – just the other week I had to abandon plans to visit the brilliant new Dagenham indoor pool because the waiting time was too long, much to the disappointment of my 6-year-old daughter.

Like this:

St Swithun’s reputation as a weather saint is said to have arisen from the translation of his body from a lowly grave to its golden shrine within Winchester cathedral, having been delayed by incessant rain for 40 daysLegend has it that the weather on Monday will be the same for the next 40 days.

St Swithun’s day, if thou dost rain,
For forty days it will remain;
St Swithun’s day, if thou be fair,
For forty days ’twill rain na mair.

St Swithun’s Day is probably among the most well known of weather folklore – but, taken at face value, it is probably the most unreliable.

Since 1961 Wanstead has enjoyed 29 dry St Swithun’s Days (56%). From these the longest dry spell that followed was just 18 days, in 2000. On average, if St Swithun’s is dry, the weather stays fair for five days, with rain arriving on the 20th.

Another interesting observation is that the 40-day period that followed a dry St Swithun’s is on average 13% WETTER than if it rained on July 15th.

So what does this mean for the rest of July and the summer? Looking back at other years that have seen a dry and warm pattern in the run up to St Swithun’s Day we should see a continuation of the dry, warm and sunny conditions, perhaps with a thundery breakdown arriving on the 27th.

Putting superstition and singularities aside current weather models back this up, also suggesting an extended period of dry weather lasting well into July. However, the latest jet stream forecast this evening suggests a period of unsettled weather, ie rain, on… 27th. We shall see.The latest jet stream forecast on Friday, July 12, suggests that the jet will move south over the UK around the 27th

St Swithun was born around 800AD and died on July 2, 862, at Winchester, Hampshire. According to historians he was fond of building churches in places where there were none. St Swithun, who was bishop of Winchester, was buried in the churchyard of the Old Minster at Winchester, where passers by might tread on his grave and where the rain from the eaves might fall on it.

His reputation as a weather saint is said to have arisen from the translation of his body from this lowly grave to its golden shrine within the cathedral, having been delayed by incessant rain for 40 days.

The basis of the St Swithun’s saying follows the fact that by July 15th summer weather patterns are already well established and tend to persist through the coming weeks.

In meterological terms the position of the frontal zone around the end of June to early July, indicated by the position of the jet stream, determines the general weather patterns (hot, cold, dry, wet) for the rest of the summer. Like a little stream in its bed, the frontal zone tends to ‘dig in’ shortly after the summer solstice.

As the path of our weather systems is controlled by the jet stream, a more southerly location of the frontal zone – as happened last year – is likely to bring unsettled, wet and cool weather. On the other hand, a frontal zone shifted further to the north – as is happening this year – will help the Azores high to build over western Europe, thus bringing dry and pleasant weather to the UK.

Other western European countries also have similar St Swithun’s day sayings – that follow the principle rule. In France they say ‘Quand il pleut a la Saint Gervais Il pleut quarante jours apres’ – If it rains on St. Gervais’ day (July 19th), it will rain for fourty days afterward.
In Germany the Siebenschlaefer or seven sleepers day (July 7th, after the Gregorian calendar) refers to the weather patterns of the following seven weeks.

Like this:

With all the talk of heatwaves this week it won’t be long before the media switches from piping on about the UK facing “10 years of miserable summers” to “Is our climate getting warmer?”.

But the simple fact is that the UK’s climate has always varied greatly – some years, as in the last two, the pattern for summer has brought mostly miserable weather. Other years we get a run of warm, dry summers.

A case in point was the heatwave of July 1808. Far removed from images of freezing Georgian winters and miserable summers the July of 205 years ago was among the warmest ever. The monthly mean for July 1808, according to the Central England Temperature series, was 18.4C – the 6th hottest July since the beginning of the series in 1659.

Readings taken by Luke Howard at Plaistow show the build up of heat to the 14th. The series on the right, taken in Wanstead, around 3 miles to the north-east, will be added to by the author as July unfoldsLuke Howard, the ‘father of meteorology’ who at the time lived in Plaistow, referred to the heatwave in his diary on July 13th: “Temperature at 9am 84F. The intense heat of the maximum lasted nearly three hours till about 4pm. At 6pm the temperature was 90F.” Another entry mentions a reading taken nearby. “Another at Plashet, a mile and a half eastward, indicated 96F as the maximum under the shade of a house.”
While Howard’s methods of measuring the temperature ran short of modern standards, his thermometer was hung under a laurel bush, the values still give a valid insight into the heatwave.

Tales of the heatwave, which particularly affected east and north-east England, can be seen in letters sent to local newspapers around the country. Many describe labourers dying from heat exhaustion while working in fields. Farm animals and horses suffered a similar fate. One letter from Hull, published in the Coventry Mercury, said: “At Sigglesthorne, the honey in some beehives melted, ran out upon the ground, and most of the bees drowned in it. At Sutton, a lamb and a dog belonging to the Rev Mr Croft of Rowley, expired in the heat; and several birds dropped down dead, while flying over the streets of this town.”
Of course it is impossible to know about the health of people and animals that died but that birds dropped out the sky suggests extreme heat.

While temperature records of July 1808 are not unheard of in an English summer one record that remains is the size of the hail – which fell in damaging storms when a thundery breakdown arrived on the 15th.

The main storm missed Wanstead and the surrounding area – though Howard, writing in his Plaistow observatory, knew the weather was on the turn: “Dew on the grass, a fine breeze from ENE. Much lightning in the west this night, a few drops of rain.” Howard would have been referring to all the action about 120-odd miles west where one of the most ferocious storms in recorded history was unfolding.

Much was reported in the local press on the days following the storm which affected an area from Somerset northwards. As well as local records Luke Howard also noted national events in his diary: “After several days of uncommon and oppressive heat the city of Gloucester experienced a storm of thunder and lightning which extended many miles round and exceeded in awful phenomena any one remembered for many years past.”

Trees were “shivered to atoms”, livestock killed by lightning, crops were ruined and countless windows and glasshouses smashed by huge hailstones. A lot of the detail of the storm was compiled by a man named Crocker, then governor of Frome school, Somerset. One account from Batcombe describes a hailstone that measured 13.5 inches in circumference. To give you an idea of the size of a 342mm circumference hailstone I, with the help of my daughters, made one of my own.It is thought the size of the 1808 hailstone may, along with a storm in 1697, be the national record for hailstone size – being 20mm greater in diameter than those measured in a Horsham, West Sussex, storm in 1958

Howard’s report continues: “The most tremendous circumstance of this storm was the destructive hail shower which accompanied its progress.”

The Tornado and Storm Research Organisation (TORRO) grades haistorms from H1-H10, where the hail increases in size from 5-10 to over 125mm in diameter. From the historic descriptions the 1808 storm was an H8/9.This exceeds the British record made during the Horsham, West Sussex, storm of September 5, 1958, which produced hailstones up to 80mm in diameter. Hailstones for the 1808 storm were about 109mm in diameter. Since 1650 there have been 119 independent H5 hailstorms in England and Wales.

Since 1900 there has been a halving in the frequency of recorded destructive hailstorms. Scientists are undecided on whether this is a result of climate change or just a variability of the British weather. But any future uptick in destructive hail should be tempered by this historic record.

It is my belief that people’s current expectations for summer were raised to unrealistic levels when we had a run of warm, dry summers a few years ago. The fact is that because of our maritime climate warm, dry summers occur in this country only occasionally. ‘Default’ summer weather is changeable, rather cloudy and, for many in the north, rather cool

So, if any media outlets do start coming out with any stories of “unprecedented heat” or “worst storm in history” bear in mind that it has probably all happened before.

Sunsets

Typical April days of sunshine and showers were in short supply. There were some stunning sunsets, including this one on the 30th

A stunning example of sunlight illuminating the underside of cloud at sunset was seen mid-month

I took this yesterday evening. Windless, still and humid at ground level it was fascinating to look skyward and see the multi-level cloud continue to build into strange shapes, illuminated from below by the setting sun. A wonderful weekend for cloudspotting.

Sunset on 31st looking across Wanstead Flats. July was a classic summer month for weather

With the sun lower in the sky at this time of year there’s often a great opportunity for a decent sunset

sunset overlooking Wanstead Flats 2nd August

It was a month with some amazing sunsets. This one, on April 30th, happened just as the sky cleared before dusk

Satellite images

Ophelia

Both the 2013 storm, left, and the 1987 storm followed a similar track as shown on these satellite pictures

On 25th a perfect curl could be seen on a depression centred off the west coast of Irleland. The rain associated with this low pressure brought the month’s highest daily rainfall total: 23.4mm (the system bringing 27.5mm) – a thoroughly miserable Bank Holiday Monday where it rained ALL day, from 6am until 9.30pm. It was yet another example of how much even frontal rainfall can vary over a small area.

This satellite picture taken on December 27th, 2014, shows the LP clearing through to leave us in clear, deep cold air